Process and apparatus for winding filaments



May 26, 1942. k.1. w. ALLQulsT 2 2,284,244

rnoczss AND APPARATUS Fon wINDING FILAMENTS 'Filed' Oct. 5, 1938l n "n u o H* ou J6,

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' INVENTOR ATTORNEY Patented May 26, 1942 2,284,244 PROCESS AND APPARATUS Fon WINDING FILAMEN'rs John William Allquist, Romel Ga., assignor to- '.lnbize Chatillon Corporation, New York, N. Y., a 'corporation of Delaware l Application October 5, 1938, Serial No. 233,403v

9 Claims.

This invention relates to winding plastic lilaments, particularly freshly formed rayon filaments, and aims to inhibit the development of non-uniform denier or cross-section during the winding of such filaments as a series of overlapping spirals. on a bobbin or other retaining means.

It is customary to Wind freshly spun rayon filament bundles or yarns upon a bobbin or the like while the rayon is still in a plastic condi' tion. Thus, rayon yarn frequently is Wound on bobbins almost immediately after withdrawal Afrom a setting bath or solvent evaporating 'being manifested by a lack -of uniformity in the cross-section or denier of the yarn. Various means have been proposed heretofore with a view toward minimizing the distortion thus caused, and have taken the form of complex mechanisms for reducing the speed of the guide toward the end of the stroke so as to reduce the strain upon the yarn at the moment that the guide changes direction. Such proposals, however, have not been entirely satisfactory. At the present time, commercially produced yarns averaging, say 150 denier, have variations of from 140 to 160 denier, or even more over a i length of about 1 meter, as a result of the action of the traverse mechanism.`

As a result of my investigations, I have discovered that the aforementioned distortion during the winding of fresh rayon and similar plastic filaments may be inhibited if tension in the lilaments is reduced and substantially equalized at the point where they are Wound onto and become part of a cake on the bobbin. It is probable that the laments have suflicient inherent resiliency to restore them to the formthey had prior to distortion by the alternate pull and release of the guide. Whatever the explanation, the fact remains that the cross-section of freshwound rayon yarn is more ,uniforml if .it is slackened or substantially untensed after` `pass ing through a traverseand before it is wound. In accordance with my invention, the requisite reduction and equalization in tension at the point of` winding is obtained by passing the filaments moving from the guide to the bobbin against a surface moving in the direction of passage of the filaments at a speed that is substantially higher than the peripheral speed of the cake being formed on the bobbin,v while moving the filaments back and forth across the surface transverse to the direction of passage and, in effect, in the direction of the stroke of the guide.v In this way, Vthe traverse motion imparted to the filaments by the guide is not interfered with substantially, and the yarn may be wound in the desired series of overlapping spirals while in a slack or relatively untensed condition. The filaments should be pressed against the moving surface with a force suflicient to permit the transmission of power from the surface to the filaments, so that the latter are accelerated. In other words. there should be sufficient friction between filaments and mov-- ing surface to permit acceleration of the filaments but not so much that the transverse motion of the filaments across the surface is prevented. 'I'he surface is preferably a rotating annular one, for example, that of a relatively long cylinder mounted with its axis of rotation substantially parallel to thatfof the bobbin or other rotatingcollector. The surface, for exampie, that of a positively driven cylindrical godet, should be at least as long as the cake or yarn package to be formed. Otherwise, the filaments tend to run oil the ends of the surface. No further guides. or traverses should be interposed between the driven godet or like member and the bobbin or other yarn winding means, because these would tend to make yarn tension unequal again and undo the good done by the driven godet. In other words, the yarn should not bear against any member which might reintroduce inequality of tension as it passes from the driven godet to the bobbin.

ments are passed through a reciprocating guide and wound as a cake on a rotating bobbin which comprises passing the filaments moving from the guide to the bobbin against a surface movl ing in the direction of passage of the filaments at a. speed that is substantially higher than the peripheral speed of the cake, transmitting power' from the moving surface to the filaments and thereby accelerating the filamentswhile moving the filaments back and forth across the surface transverse to their direction of passage', whereby tension in the filaments at the point Iof winding on the bobbin is reduced. My invention further contemplates the combination in apparatus for winding plastic filaments which comprises a rotatable bobbin upon which the fila--A ments are wound, means for rotating the bobbin, a guide through which the laments pass.

on their way to the bobbin, sai'd guide being reciprocable through a stroke transverse to the direction of passage of the illaments, a godet so disposed in the path of the illaments from the guide to the bobbin that the laments bear against the godet, and the means for rotating the godet in the direction of lament passage at a peripheral speed substantially in excess of that of the bobbin, the coefllcient of lfriction of the godet being such that the higher peripheral speed thereof is transmitted at least in part of the filaments. By peripheral speed of the bobbin" I mean linear speed of the yarn at the point where it is wound onto the cake being built up on the bobbin. -These and other features of my invention will be understood more thoroughly in the light of the following detailed description taken in conjunction with the accompanying drawing, in which Fig. 1 is aA schematic 'transverse elevation of one form of the apparatus of my invention;J

Fig. 2 is a schematic longitudinal elevation of the apparatus of Fig. 1;

Fig. 3 is a schematic transverse elevation of anther form'o'f the apparatus of my invention; an

Fig. 4 is a schematic longitudinal elevation of the apparatus of Fig. 3.

Referring now to the drawing, the apparatus of Figs.A 1 and 2 comprises a bobbin Ill of conventional type rigidly mounted in a horizontal position on a concentric shaft II. Conventional means, such as a belt-driven pulley Ila, are provided for rotating the shaft. Disposed directly above the bobbin and parallel to itis a godet I2 rigidly mounted on a shaft I3, which is adapted to be positively driven by a means, such as a belt-driven pulley I3a, at a rate such that the peripheral speed of the godet is substantially higher than that of the bobbin, The godet is in the form of a smooth surfaced Cylinder, the length of which is substantially the same as the length of the bobbin, both godet and bobbin a very low coeilicient of friction, it may be del sirable to pass one or more turns of the yarn around the godet so that there will not be excessive slippage of the yarn with respect to the godet surface. With ordinary machined metal surfaces, the yarn need take only about half a turn around the godet which, being driven at a substantially higher speed .than the bobbin, will cause a portion I9 of the yarn between the godet and bobbin to be in a slack or relatively untensed condition.V In such condition. the natural resiliency of the rayon yarn will result in at least a partial removal of the distortion in cross-section brought about by the uneven strain imposed by the reciprocating traverse guide. Consequently,

,the character of the yarn will be improved.

Thus, in accordance with my invention, variations in denier may be reduced to 2 or 3% or less.

The apparatus of Figs. 3 and 4 is the same in principle as that of Fig. l, but in it the freshly spun rayon yarn 29 ilrst is passed over a llrst godet 30 which may be part of the stretching arrangement customarily employed for reducing the denier of freshly spun yarn. As shown in Fig. 4, the godet 30 need not be very long because the yarn follows a substantially constant path around its surface. After the yarn passes over the first godet, it passes through a guide 3l mounted on the end of a traverse arm 32 which in this instance is reciprocated lengthwise in a direction transverse to the direction of yarn passage and substantially parallel to the axis of the godet. Below the guide, the yarn passes against being longer than the traverse stroke, as hereinafter described.

Freshly formed and, therefore, plasticA rayon filaments are produced in the form of yarn I4 comprising a plurality of laments. The yarn rection transverse to that of yarn passage (as indicated by the arrows on Fig. 2), and substantially parallel to the axes of rotation of the godet and of the bobbin. The yarn passes through the reciprocating guide and is wound as a cake I8 on the bobbin. The cake comprises a series of overlapping spirals and if the traverse stroke is gradually shortened during the winding operation, it will have tapered ends as shown in Fig. 2.

Ordinarily, yarn vneed not pass completely around the godet. Generally, contact of the yarn with only a relatively small portion of the periphery of the godet will be suicient to impart tothe yarn the requisite acceleration. In some inntances. however, as when the godet surface has a second godet 33, changes direction, and is wound as a series of overlapping spirals in a cake 3l, on a bobbin 35. The bobbin is rigidly mounted on a horizontally disposed shaft 36 and con ventional means (not shown) are provided for i driving the shaft. The axes of both godets and the bobbinare substantially parallel.

The second godet 33 is cylindrical in form, of relatively small diameter, and at least as long as the traverse stroke,l so that the yarn will not be thrown olf its ends. It is mounted out of line with the common tangent of the irst or upper godet and the bobbin, so that the yarn in passing over it changes direction and bears against a portion of the second godet's periphery. Conveniently, the second godet is rigidly mounted on a shaft 31, which is positively driven, by a means such as gearing 33, at a rate such that the peripheral speed of the second godet is in excess of that of the bobbin.

As in the case of the apparatus of Figs. 1 and 2,- the second godet 33 of the apparatus of Figs. 3 and 4 is rotated in the direction of yarn passage, accelerates the yarn passing over it so that a section 33 of the yarn between the second godet and the bobbin is in a relativelybuntensed or slack condition, In thisv condition the yarn has an opportunity to resume its original shape and its resiliency acts toovercome the distortion in denier brought about by the alternate drag and release of the traverse mechanism. Hence, by relatively simple means, I am able to improve the uniformity of rayon yarn and the like..

In the practice of my invention the peripheral speed of the driven godet interposed between the is transmitted from the surface to the'filaments land the latter are accelerated and become relatively untensed as they pass to the collector fixed ratio between the speeds of the driven godet and the bobbin.

I claim: 1. In a processln which plastic filaments are passed through a reciprocating guide and wound as a cake on a rotating bobbin, the improvement which comprises passing the filaments moving from the guide to the bobbin against a surface moving in the direction of passage of the filaments at a speed that is substantially higher than the peripheral speed of the`cake, transmit-v ting power from the moving surface to the filaments and thereby accelerating the filaments, while moving the filaments back and forth across the surface transverse to their direction' of passage, whereby tension in the filaments at the point of winding on the bobbin is reduced.

2. In a process in which .relatively plastic rayon laments are passed through a guide reciprocating transversely to the direction of passage of the filaments and wound on a rotating annular surface as a series of overlapping spirals, the improvement which comprises immediately before the winding passing the filaments between the guide and said surface ,against a second annular surface rotating in the direction of passage of the filaments with a peripheral speed higher than that of the first annular surface, transmitting power from the moving surface to the filaments and thereby accelerating the filaments while moving the filaments back and forth while moving the filaments back and forth across Y the surface in a direction transverse to that of the moving laments.

5. In a process in which relatively plastic rayon filaments are passed through a guide reciprocated transversely tothe direction of passage of the filaments and wound around a rotating collector, the improvement which comprises passing the filaments between the guide and the collector at least partially around a cylinder disposed with its axis transverse to the direction of passage and rotated in the direction of passage of the filaments at a higher peripheral speed than that of the collector while moving the filaments back and forth across the cylinder in the direction of its axis of rotation, transmitting power` from the cylinder to the laments so that the filaments are accelerated during their contact with the cylinder and are' in substantially slack condition when wound on the collector as u a series of overlapping spirals.`

6. In apparatus for winding plastic rayon fila-` ments, the combination which comprises a rotatable bobbin upon which the filaments are wound,

across the surface transverse to the direction of passage of the filaments, whereby the tension of the filaments being wound is reduced.

3. In a process in which relatively plastic rayon filaments are passed through a guide reciprocatv ting transversely to the direction of passage of the filaments and wound as a series of overlapping spirals on a rotating collector, the improvement which comprises pressing the filaments passing from the guide to the collector against a surface moving in the direction of passage Yof the filaments at a speed in excess of that attained by the filaments at the point of winding, said pressing being conducted with a force suiiicient to bring about the transmission of power from the moving surface to the filaments and thereby impart acceleration to the filaments, and simultaneously moving the filaments back and forth across said surface transverse to the direction of filament passage, whereby tension in the filaments being Wound is reduced.

4. In a process in which plastic rayon filaments are passed through a guide recprocated transversely to the direction of passage of the means for rotating the bobbin, a guide through.

which the filaments pass on their Way to the bobbin, said guide being reciprocable through a stroke in a direction transverse to that of filament passage and substantially parallel to the axis of rotation of the bobbin, agodet disposed in the path of the filaments from the guidp Ato the bobbin. said godet having a cylindrical'surface at least as long as the stroke ofthe guide and being rotatable around an axis substantially parallelto that of the bobbin, and means for rotating the godet at a peripheral speed in excess of that of the bobbin, the coefficient of friction between the filaments and the cylindrical surface, being such that the higher peripheral speed ofthe cylindrical surface is transmitted at least in part to the filaments.

'7. In a process in which plastic filaments are passed through a reciprocating guide and wound as a' cake on a rotating bobbin, the improvement which comprises passing the filaments back and.

forth over a roller that is disposed between the guide and the bobbin with its axis of rotation substantially parallel to the bobbin and positively driven at a faster peripheral speed than that of the cake and thus relieving'winding'tension on the bobbin, whereby variations in tension in successive portions 0f the filaments being wound tend to be equalized and variations in denier due tc stretching of the filaments minimized.

8. In apparatus for winding plastic filaments, thecombination which comprises a rotatable bobbin upon which the filaments Iare wound, means for rotating the bobbin, a guide through which the filaments pass on their way to the bobbin, said guide being reciprocable through a stroke transverse to the direction of passage of the filaments, a godet so disposed in the path .of the filaments from the guide to the bobbin that the filaments bear against the godet, and means for rotating the godet in the direction of filament passage at a peripheral speed substantially inA 9. In apparatus for winding plastic filaments, the. combination which comprises a rotatable bobbin upon which the filaments are'wound, means for rotating the bobbin, a guide through which the iilaments pass on their way to the bobbin, said guide being reciprocable througha stroke transverse to the direction of passage of 6 the laments, a godet disposed with its axis of rotation substantially parallel to that of the bobbin and having a rotating surface (against which the illaments bear) at least as long as the stroke of the reciprocable guide, and means for rotating the godet in the direction of lament passage at 

